This invention relates to paper retaining ring binder mechanisms, and more particularly, to a spur eyelet having a uniform circular base for securing a ring metal of the ring binder mechanism to a spine portion of a binder.
Paper retaining ring binder mechanisms typically comprise a ring metal assembly, formed of metal, and including binder rings which are openable for the insertion and removal of material, such as hole-punched sheets of paper. The ring binders and a lever mechanism by which they are opened and closed all form part of the ring metal assembly. A plate covers the lever mechanism and usually includes provisions at each end for attachment of the ring metal to a spine section of the binder. One form of attachment includes the use of rivets secured to the binder and passing upward, through the ring metal. However, it has been found that other means of attachment are more secure and better able to withstand the rigors associated with daily binder use.
For cosmetic purposes, it is often desirable to incorporate a means for securing the ring binder mechanism to the binder which is not visible on the exterior surfaces of the binder. U.S. Pat. No. 5,755,513 to To, No. 5,160,209 to Schuessler, and No. 5,100,253 to Cooper each illustrate a fastener comprising an upright rivet structure mounted on a rectangular attachment plate and having a number of prongs adapted to grip an interior surface of a binder. The rivet structures in each of these patents are designed to pass through openings in the binder mechanism for attachment thereto.
While useful for their intended purpose, these fasteners suffer from several drawbacks. First, the prongs of each fastener are punched directly out of the attachment plate material; and, as best shown in FIG. 4A of the '513 patent, are surrounded by non-uniform amounts of material. This is due to the rectangular configuration of the attachment plate.
Second, the rectangular configuration further hinders automated assembly of the binders, as each fastener must be oriented such that the longest dimension of the attachment plate is properly oriented along the spine of the binder. Incorrect orientation will result in the interference between the cover portions and the attachment plate when the binder is folded closed.
Finally, the upright rivet structure commonly used in the prior art fasteners requires either a shoulder incorporated into the rivet structure itself, as is shown in the '513 patent, or a separate supporting means to hold the ring metal in position as the upper surface of the rivet is deformed to secure the ring metal, as is seen in the '209 and '253 patents.